engine MERCEDES-BENZ C-Class SEDAN 2012 W204 Owner's Guide

Runlocked with the mechanical key
R opened with the emergency release button
Opening and closing manually
Opening
XPress the % button on the SmartKey.XPull handle :.XRaise the trunk lid.
Closing
GWARNING
To prevent possible personal injury, always
keep hands and fingers away from the trunk
opening when closing the trunk lid. Be
especially careful when small children are
around.
XPull the trunk lid down using recess :.XIf necessary, lock the vehicle with
the & button on the SmartKey(Y page 70) or with KEYLESS-GO
( Y page 71).
i
If a KEYLESS-GO key is detected in the
trunk, the trunk lid cannot be locked and
then opens again.
Opening automatically from outside
Important safety notes
GWARNING
Make sure the trunk lid is closed when the
engine is running and while driving. Among
other dangers, deadly carbon monoxide (CO)
gases may enter the vehicle interior resulting
in unconsciousness and death.
! The trunk lid swings upwards when
opened. Therefore, make sure that there is
sufficient clearance above the trunk lid.
To open the trunk lid completely, a minimum
clearance of 5.90 ft (1.80 m) above the
ground is necessary.
Opening
You can open the trunk lid automatically
using the SmartKey or the handle in the trunk
lid.
XPress and hold the F button on the
SmartKey until the trunk lid opens.
or
XWhen the trunk is unlocked, pull the trunk
lid handle and let it go again immediately.
Closing
Opening automatically from the
inside
GWARNING
Make sure the trunk lid is closed when the
engine is running and while driving. Among
other dangers, deadly carbon monoxide (CO)
Trunk81Opening/closingZ

The switches for all side windows are located
on the driver's door. There is also a switch on
each door for the corresponding side window.
The switches on the driver's door take
precedence.
i The side windows cannot be operated
from the rear when the override feature for
the side windows is activated ( Y page 57).XTurn the SmartKey to position 1 or 2 in the
ignition lock.XTo open: press the corresponding switch.XTo close: pull the corresponding switch.
i
If you press the switch beyond the point
of resistance, an automatic opening/
closing process is started in the
corresponding direction. You can stop
automatic operation by operating the
switch again.
i You can continue to operate the side
windows after you switch off the engine or
remove the SmartKey. This function is
available for up to five minutes or until the
driver's or front-passenger door is opened.
Convenience opening feature
You can ventilate the vehicle before you start
driving. To do this, the key is used to carry out
the following functions simultaneously:
R unlock the vehicle
R open the side windows
R open the sliding sunroof or the panorama
roof with power tilt/sliding panel and the
roller sunblinds
i The convenience opening feature can
only be operated using the SmartKey. The
SmartKey must be close to the driver's
door handle.
XPoint the tip of the SmartKey at the driver's
door handle.XPress and hold the % button until the
side windows and the sliding sunroof or thepanorama roof with power tilt/sliding
panel are in the desired position.
If the roller sunblinds of the panorama roof
with power tilt/sliding panel are closed, the
roller sunblinds are opened first.
XPress and hold the % button again until
the panorama roof with power tilt/sliding
panel is in the desired position.XTo interrupt convenience opening:
release the % button.
Convenience closing
General notes
When you lock the vehicle, you can
simultaneously:
R close the side windows
R close the sliding sunroof or the panorama
roof with power tilt/sliding panel
On vehicles with a panorama roof with power
tilt/sliding panel, you can then close the
roller sunblinds.
GWARNING
When closing the door windows and the
sliding sunroof or panorama roof with power
tilt/sliding panel, make sure that there is no
danger of anyone being harmed by the closing
procedure.
If potential danger exists, proceed as follows:
R Release the & button to stop the closing
procedure. To open, press and hold the
% button. To continue the closing
procedure after making sure that there is
no danger of anyone being harmed by the
closing procedure, press and hold the
& button.
Vehicles with KEYLESS-GO:
R Release the sensor surface on the outside
door handle to stop the closing procedure.
R Immediately pull on the same outside door
handle and hold firmly. The door windows
and the sliding sunroof or panorama roof
84Side windowsOpening/closing

damaged if water enters the vehicle
interior.
i Resonance noises can occur in addition
to the usual airflow noises when the sliding
sunroof is open. They are caused by minor
pressure fluctuations in the vehicle interior.
Change the position of the sliding sunroof
or open a side window slightly to reduce or
eliminate these noises.
Operating the sliding sunroof
Opening and closing
i You can continue to operate the sliding
sunroof after switching off the engine or
removing the SmartKey from the ignition
lock. This function is available for up to five
minutes or until the driver's or front-
passenger door is opened.
Overhead control panel
:To raise;To open=To close/lowerXTurn the SmartKey to position 1 or 2 in the
ignition lock.XPress or pull the 3 switch in the
corresponding direction.
i If you press the 3 switch beyond the
point of resistance, an automatic opening/
closing process is started in the
corresponding direction. You can stop
automatic operation by operating the
switch again.
When opening and raising the roof,
automatic operation is only available if the
sliding sunroof is in the closed position.
The sun protection cover automatically opens
along with the sliding sunroof. You can open
or close the sun protection cover manually
when the sliding sunroof is raised or closed.
Resetting
Reset the sliding sunroof if it does not move
smoothly.
XTurn the SmartKey to position 2 in the
ignition lock.XRaise the sliding sunroof fully at the rear
( Y page 87).XKeep the 3 switch pressed for another
second.XMake sure that the sliding sunroof can be
fully opened and closed again (Y page 87).XIf this is not the case, repeat the steps
above again.
! If the sliding sunroof still cannot be
opened or closed fully after resetting,
contact a qualified specialist workshop.
Operating the panorama roof with
power tilt/sliding panel
Opening and closing
Overhead control panel
:To raise;To open=To close/lowerSliding sunroof87Opening/closingZ

Illustration: light switch with the c symbol for
the automatic headlamp mode/daytime running
lamps
1 WLeft-hand standing lamps2XRight-hand standing lamps3TParking lamps, license plate and
instrument cluster lighting4 cAutomatic headlamp mode/daytime
running lamps5 LLow-beam/high-beam headlampsBRRear fog lampCNFront fog lamps 7
The turn signals, high-beam headlamps and
the high-beam flasher are operated using the
combination switch ( Y page 109).
! Switch off the parking lamps and standing
lamps when you leave the vehicle. This
prevents the battery from discharging.
The exterior lighting (except the parking/
standing lamps) switches off automatically if
you:
R remove the SmartKey from the ignition lock
R open the driver's door with the SmartKey
in position 0
If you hear a warning tone when you leave the
vehicle, the lights may still be switched on.
XTurn the light switch to c or à .Low-beam headlampsXTo switch on the low-beam headlamps:
turn the SmartKey in the ignition lock to
position 2 or start the engine.XTurn the light switch to L.
The L indicator lamp in the instrument
cluster lights up.
Daytime running lamps
Daytime running lamps in Canada
The daytime running lamps function is
required by law in Canada. It cannot therefore
be deactivated.
XTurn the light switch to c or à .
With the engine running: depending on the
ambient light, the daytime running lamps or
the low-beam headlamps are switched on.
When the low-beam headlamps are
switched on, the L indicator lamp in the
instrument cluster lights up.
When the engine is running and the vehicle is
stationary: if you move the selector lever from
a drive position to P (vehicles with automatic
transmission) or if the parking brake is
applied, the low-beam headlamps go out after
three minutes.
When the engine is running, the vehicle is
stationary and in high ambient light
brightness: if you turn the light switch
to T , the daytime running lamps and the
parking lamps are switched on.
If the engine is running and you turn the light
switch to L, the manual settings take
precedence over the daytime running lamps.
Daytime running lamps in the USA
This function is only available on vehicles with
daytime running lamps.
In the USA, the daytime running lamps are
deactivated upon delivery from the factory.
XTo activate the daytime running lamps
(vehicles with a luxury multifunction 7 Only vehicles with front fog lamps have the fog lamps function.Exterior lighting107Lights and windshield wipers

steering wheel): you can activate the
daytime running lamps function using the
on-board computer ( Y page 207).XTurn the light switch to c or à .
With the engine running: depending on the
ambient light, the daytime running lamps or
the low-beam headlamps are switched on.
When the low-beam headlamps are
switched on, the L indicator lamp in the
instrument cluster lights up.
It is only possible to activate the high-beam
headlamps if the brightness of the ambient
light is at a low level.
However, the high-beam flasher can always
be used.
If the engine is running and you turn the light
switch to T or L , the manual settings
take precedence over the daytime running
lamps.
Automatic headlamp mode
XTo switch on automatic headlamp
mode: turn the light switch to c or
à .
SmartKey in position 1 in the ignition lock:
the parking lamps are switched on or off
automatically depending on the brightness
of the ambient light.
With the engine running: depending on the
brightness of the ambient light, the daytime
running lamps 8
or the low-beam headlamps
are switched on or off automatically.
When the low-beam headlamps are
switched on, the L indicator lamp in the
instrument cluster lights up.GWARNING
If the light switch is set to c or à , the
low-beam headlamps will not come on
automatically if it is foggy. This could
endanger you and others. Therefore, turn the
light switch to L in fog.
The automatic headlamp feature is only an
aid. The driver is responsible for the vehicle's
lighting at all times.
Front fog lamps
Only vehicles with front fog lamps have the
fog lamps function.
GWARNING
If you suspect that driving conditions will be
foggy, turn the light switch to L before you
start your journey. Otherwise, your vehicle
may not be visible and you could endanger
yourself and others.
XTo switch on the front fog lamps: turn
the SmartKey in the ignition lock to position
2 or start the engine.XTurn the light switch to L or c or
à .XPress the N button.
The green N indicator lamp in the
instrument cluster lights up.XTo switch off the front fog lamps: press
the N button.
The green N indicator lamp in the
instrument cluster goes out.
Rear fog lamp
XTo switch on the rear fog lamp: turn the
SmartKey in the ignition lock to position 2
or start the engine.XTurn the light switch to L or c or
à .
If the light switch is set to c or à ,
the rear fog lamp only lights up if the low-
beam headlamps are on.8 Only if daytime running lamps have been activated via the on-board computer.108Exterior lightingLights and windshield wipers

XPress the R button.
The yellow R indicator lamp in the
instrument cluster lights up.XTo switch off the rear fog lamp: press the
R button.
The yellow R indicator lamp in the
instrument cluster goes out.
Headlamp cleaning system
The headlamps are cleaned automatically if
the "Wipe with washer fluid" function is
operated ten times while the lights are on and
the engine is running ( Y page 116).
Combination switch
Turn signals
:High-beam headlamps;Right turn signal=High-beam flasher?Left turn signalXTo indicate briefly: press the combination
switch briefly to the pressure point in the
direction of arrow ; or ?.
The corresponding turn signal flashes three
times.XTo indicate: press the combination switch
beyond the pressure point in the direction
of arrow ; or ?.High-beam headlampsXTo switch on the high-beam headlamps:
turn the SmartKey in the ignition lock to
position 2 or start the engine.XTurn the light switch to L or c or
à .XPress the combination switch beyond the
pressure point in the direction of
arrow :.
In the c or à position, the high-
beam headlamps are only switched on
when it is dark and the engine is running.
The K indicator lamp in the instrument
cluster lights up when the high-beam
headlamps are switched on.XTo switch off the high-beam
headlamps: move the combination switch
back to its normal position.
The K indicator lamp in the instrument
cluster goes out.
High-beam flasher
XTo switch on: turn the SmartKey in the
ignition lock to position 1 or 2 or start the
engine.XPull the combination switch in the direction
of arrow =.
Hazard warning lamps
Exterior lighting109Lights and windshield wipersZ

Manual interior lighting controlXTo switch the front interior lighting on/
off: press the c button.XTo switch the rear interior lighting on/
off: press the u button.XTo switch the reading lamps on/off:
press the p button.
Crash-responsive emergency lighting
The interior lighting is activated automatically
if the vehicle is involved in an accident.
XTo switch off the crash-responsive
emergency lighting: press the hazard
warning lamp button.
or
XLock and then unlock the vehicle using the
SmartKey.
Replacing bulbs
Important safety notes
Xenon bulbs
If your vehicle is equipped with Xenon bulbs,
you can recognize this by the following: the
cone of light from the Xenon bulbs moves
from the top to the bottom and back again
when you start the engine. For this to be
observed, the lights must be switched on
before starting the engine.
GDANGER
Xenon bulbs carry a high voltage. You could
get an electric shock and be seriously or even
fatally injured if you touch the electric
contacts on Xenon bulbs. Therefore, never
remove the cover from Xenon bulbs.
Do not change Xenon bulbs yourself, but have
them replaced at a qualified specialist
workshop which has the necessary specialist
knowledge and tools to carry out the work
required.
Mercedes-Benz recommends that you use an
authorized Mercedes-Benz Center for this
purpose. In particular, work relevant to safety
or on safety-related systems must be carried
out at a qualified specialist workshop.
Bulbs and lamps are an important aspect of
vehicle safety. You must therefore make sure
that these function correctly at all times.
Have the headlamp setting checked regularly.
Other bulbs
There are bulbs other than the Xenon bulbs
that you cannot replace. Replace only the
bulbs listed (Y page 114). Have the bulbs that
you cannot replace yourself changed at a
qualified specialist workshop.
Mercedes-Benz recommends that you use an
authorized Mercedes-Benz Center for this
purpose. In particular, work relevant to safety
or on safety-related systems must be carried
out at a qualified specialist workshop.
If you require assistance changing bulbs,
consult a qualified specialist workshop.
Do not touch the glass tube of new bulbs with
your bare hands. Even minor contamination
can burn into the glass surface and reduce
the service life of the bulbs. Always use a lint-
free cloth or only touch the base of the bulb
when installing.
Only use bulbs of the correct type.
If the new bulb still does not light up, consult
a qualified specialist workshop.
Bulbs and lamps are an important aspect of
vehicle safety. You must therefore make sure
that these function correctly at all times.
Have the headlamp setting checked regularly.
GWARNING
Bulbs and lamps can be very hot. You should
therefore allow them to cool down before you
change them. Otherwise, you could be burned
if you touch them.
Keep bulbs out of the reach of children.
Otherwise, they could damage the bulbs, for
example, and injure themselves.
Replacing bulbs113Lights and windshield wipersZ

XHold wiper arm : and press wiper
blade ; in the direction of the arrow until
it releases.XRemove wiper blade ;.
Installing the wiper blade
XPlace new wiper blade ; onto wiper
arm :.XHold wiper arm : and press wiper
blade ; in the opposite direction to the
arrow until it engages.XMake sure that wiper blade ; is seated
correctly.XPosition wiper blade ; parallel to wiper
arm :.XFold wiper arm : back onto the rear
window.
Problems with the windshield wipers
The windshield wipers are obstructed
Leaves or snow, for example, may be
obstructing the windshield wiper movement.
The wiper motor has been deactivated.
XFor safety reasons, you should remove the
SmartKey from the ignition lock.
or
XSwitch off the engine using the Start/Stop
button and open the driver's door.XRemove the cause of the obstruction.XSwitch the windshield wipers back on.
The windshield wipers are inoperative
The windshield wiper drive is malfunctioning.
XSelect another wiper speed on the
combination switch.XHave the windshield wipers checked at a
qualified specialist workshop.The spray nozzles are misaligned
The windshield washer fluid from the spray
nozzles no longer hits the center of the
windshield. The spray nozzles are misaligned.
XHave the spray nozzles adjusted at a
qualified specialist workshop.Windshield wipers119Lights and windshield wipersZ

Useful information
i This Operator's Manual describes all
models and all standard and optional
equipment of your vehicle available at the
time of publication of the Operator's
Manual. Country-specific differences are
possible. Please note that your vehicle may
not be equipped with all features
described. This also applies to safety-
related systems and functions.
i Please read the information on qualified
specialist workshops ( Y page 24).
Overview of climate control systems
Important safety notes
GWARNING
Severe conditions (e.g. strong air pollution)
may require replacement of the filter before
its scheduled replacement interval. A clogged
filter will reduce the air volume to the interior
and the windows could fog up, impairing
visibility and endangering you and others.
Have a blocked filter replaced at a Mercedes-
Benz Center as soon as possible.
GWARNING
Follow the recommended settings for heating
and cooling given on the following pages.
Otherwise, the windows could fog up,
impairing visibility and endangering you and
others.
The automatic climate control adjusts the
temperature and the humidity of the vehicle
interior and filters undesired substances from
the air.
The automatic climate control is only
operational when the engine is running. 11
Optimum operation is only achieved if you
drive with the side windows and sliding
sunroof/panorama roof with power tilt/
sliding panel closed.
i Ventilate the vehicle for a brief period
during warm weather, e.g. using the
convenience opening feature ( Y page 84).
This will speed up the cooling process and
the desired vehicle interior temperature
will be reached more quickly.
i The integrated filter can filter out most
particles of dust and completely filters out
pollen. A clogged filter reduces the amount
of air supplied to the vehicle interior. For
this reason, you should always observe the
interval for replacing the filter, which is
specified in the Service Booklet. As it
depends on environmental conditions, e.g.
heavy air pollution, the interval may be
shorter than stated in the Service Booklet.
i It is possible that the residual heat
function may be activated automatically an
hour after the SmartKey is removed. The
vehicle is then ventilated for 30 minutes to
dry the air-conditioning system.11 Automatic climate control: the residual heat function can only be activated/deactivated when the ignition
is switched off.122Overview of climate control systemsClimate control

Notes on using 3-zone automatic
climate control
The following contains instructions and
recommendations to enable you to get the
most out of your automatic climate control.
R Activate climate control using the à and
¿ buttons. The indicator lamps in the
à and ¿ buttons light up.
R In automatic mode, you can also use the
ñ button to set a climate mode
(FOCUS/MEDIUM/DIFFUSE). The
MEDIUM level is recommended.
R Set the temperature to 72 ‡ (22 †).
R Only use the "defrosting" function briefly
until the windshield is clear again.
R Only use "air-recirculation" mode briefly,
e.g. if there are unpleasant outside odors
or when in a tunnel. The windows could
otherwise fog up as, in air-recirculation
mode, no fresh air is drawn into the vehicle.
R Use the ZONE function to adopt the
temperature settings on the driver's side
for the front-passenger side and the rear
compartment as well. The indicator lamp in
the á button goes out.
R Use the residual heat function if you want
to heat or ventilate the vehicle interior
when the ignition is switched off. The
"residual heat" function can only be
activated or deactivated with the ignition
switched off.
Operating the climate control system
Activating/deactivating climate
control
Important information
GWARNING
When the climate control system is
deactivated, the outside air supply and
circulation are also deactivated. Only choose
this setting for a short time. Otherwise the
windows could fog up, impairing visibility and
endangering you and others.
i Switch on climate control primarily using
the à button ( Y page 127).
Activating/deactivatingXTurn the SmartKey to position 2 in the
ignition lock.XTo switch on: press the à button.
The indicator lamp in the à button lights
up. Airflow and air distribution are set to
automatic mode.
or
XPress the ^ button.
The indicator lamp in the ^ button goes
out. The previously selected settings come
into effect again.XTo switch off: press the ^ button.
The indicator lamp in the ^ button lights
up.
Activating/deactivating the cooling
with air dehumidification function
Important information
The cooling with air dehumidification function
is only available when the engine is running.
The air inside the vehicle is cooled and
dehumidified according to the temperature
selected.
GWARNING
If you switch off the cooling function, the
vehicle will not be cooled when weather
conditions are warm. The windows can fog up
more quickly. Window fogging may impair
visibility and endanger you and others.
Condensation may drip from the underside of
the vehicle when it is in cooling mode. This is
normal and not a sign that there is a
malfunction.
126Operating the climate control systemClimate control